NFPA 25: Fire Pump Inspection, Testing and Maintenance

1. What NFPA 25 is and what it covers on the fire pump

NFPA 25 is the NFPA standard for the inspection, testing and maintenance (ITM) of water-based fire protection systems, with a chapter of its own for fire pumps. Design, installation and acceptance testing leave the pump ready on handover day. Once the building passes to the owner, NFPA itself notes, nothing guarantees that it stays ready without routine inspection, testing and maintenance.

The standard separates three activities. Inspection is the visual examination that verifies the system appears to be in operating condition and is free of physical damage. Testing is the procedure that determines operational status through periodic physical tasks. Maintenance is the work that keeps equipment operable. For the pump, testing confirms automatic or manual starting and continuous delivery of the required system output, and detects deficiencies that inspection does not show.

The minimum frequency of fire pump inspection, testing and maintenance follows the manufacturer’s recommendations and the standard’s summary table. It ranges from weekly items, such as the pump room, the pump and the electrical and diesel systems, to annual items, such as the flow test and instrument calibration, and to power transmission components with elastomeric materials, such as torsional couplings, every five years or per the manufacturer.

The standard also defines impairment: a condition in which the system, or part of it, is out of order and might not work in a fire. A preplanned impairment comes from work planned in advance, such as changes to the piping or the water supply; an emergency impairment comes from an unplanned occurrence or is found during inspection, testing or maintenance.

The NFPA 25 annex example table classifies as an impairment a pump that did not start automatically during the test, a suction or discharge valve not fully open, a diesel controller selector switch not in auto and an empty fuel tank. The annex itself notes that the table is guidance and does not set the classification.

In Brazil, NFPA 25 applies when the design, the contract or another applicable requirement adopts it: the state rules consulted (São Paulo IT 22 and IT 23, Goiás NT 22 and the Federal District NT 13) do not cite it. For hydrants and hose reels, NBR 13714 makes periodic preventive maintenance mandatory, with a plan prepared by the designer. Sections 5 and 6 show how the routines add up.

2. NFPA 20 × NFPA 25: what is the difference

The split between the two standards is temporal. NFPA 20 covers the selection and installation of stationary pumps and the acceptance test, and states in its own scope that it does not cover periodic inspection, testing and maintenance requirements. Those belong to NFPA 25, which governs the routine for the rest of the system’s life and takes the pump definitions from NFPA 20, such as rated flow, rated pressure and the no-flow condition.

The two standards meet at the curve. The acceptance test produces the field curve that the NFPA 25 annual test uses as a reference, alongside the original manufacturer’s curve and the nameplate curve. That is why the handover documents, with the manufacturer’s curve, the field curve and the acceptance report, are the starting point of maintenance, not paperwork for the archive.

3. No-flow (churn) test: frequency, starting and duration

In the no-flow test, also called churn, the pump runs without delivering water to the system. By the standard’s definition, the only water passing through it is a small flow discharged through the circulation relief valve, or the cooling water for a diesel engine driver. That small flow keeps the pump from overheating, and NFPA asks for confirmation during the test, for electric pumps and radiator-cooled diesel pumps, that the valve is actually discharging.

Frequency depends on the driver. A diesel engine-driven pump gets the no-flow test every week. Most electric pumps may be tested monthly, but four cases remain weekly: pumps serving buildings beyond the pumping capacity of the fire department, pumps with limited service controllers, vertical turbine pumps, and pumps taking suction from ground-level tanks or from a source without useful pressure without the pump. These four cases may move to monthly where a redundant fire pump is provided.

Both frequencies may change with an approved risk analysis, which the annex recommends be prepared and reviewed by qualified people. The standard’s annex cites a 2011 field data report: assuming the failure occurs, on average, at the midpoint of the test interval, the estimated reliability of an electric pump is about 99.4% with weekly testing and 97.3% with monthly testing; for diesel, 99.1% and 96.0%. Reducing frequency takes more than cost savings.

The test start is automatic. The pump starts because water is drained from the pressure sensing line, simulating a system pressure drop, not from the start button on the controller. The standard allows an automatic timer, with a solenoid drain valve on the pressure control line for pressure-actuated controllers, or another means for the others. In FB fire configurations, the diesel engine panel includes a scheduled weekly test.

An electric pump runs for at least 10 minutes; a diesel pump, for at least 30 minutes. Qualified personnel attend the pump whenever it is operating, unless inspection and testing are automated in accordance with the standard. In the NFPA 25 definition, qualified personnel are competent and capable individuals who have met the requirements and training for the field acceptable to the authority having jurisdiction.

With the pump stopped, the suction and discharge gauge readings are recorded. For pumps controlled by electronic pressure sensors, the highest and lowest pressures in the controller event log are also recorded, where available without opening an energized controller. A value outside the expected range calls for recording all event log information that helps identify the abnormality.

With the pump running, the starting pressure from the pressure switch or transducer and the suction and discharge gauges are recorded. The packing glands are checked for slight discharge, adjusting the gland nuts if necessary, along with unusual noise or vibration and overheating of packing boxes, bearings or the pump casing. The pressure switch or transducer reading is compared with the discharge gauge.

In the electrical system, the time for the motor to accelerate to full speed, the time on the first step for reduced-voltage or reduced-current starting, and the running time after starting for automatic stop controllers are observed. On a diesel, the cranking time and the time to reach running speed are observed, oil pressure, speed and water and oil temperatures are watched, and cooling water flow through the heat exchanger is checked.

4. Annual flow test: the curve against the reference

Once a year, the pump goes through the flow test, which measures performance under real operating conditions. The unadjusted field test curve includes zero flow (churn), 100% of rated flow and the maximum flow, up to 150% of rated, with discharge gauge readings without speed or velocity pressure adjustments. The no-flow test confirms that the pump starts; the annual test confirms that it pumps.

The test also checks the peak load, the maximum power required to drive the pump at any flow up to 150% of rated. In a centrifugal pump, that maximum power typically occurs between 130% and 150% of rated flow and can be read on the horsepower curve supplied by the manufacturer. It is therefore worth keeping the manufacturer’s horsepower curve with the flow and pressure curve.

The standard’s criterion requires all listed conditions to be met. Among them: the pump meets the flow and pressure of the most demanding system it supplies, based on owner-provided design information; supplies 100% of rated flow; and has, at each flow point, a net pressure of at least 95% of one of three references: the original manufacturer’s curve, the original unadjusted field test curve or the curve generated from the nameplate data.

The annex recommends comparing the test curve with the acceptance test curve, where available, bearing in mind that the acceptance curve may exceed the pump’s minimum; a reduction should be evaluated against the rated characteristics. Plotting suction and discharge pressures as well helps separate internal wear from a loss in the water supply. Pressures above the reference are accepted, but the annex warns that the test could be flawed and calls for thorough review by qualified personnel.

Instruments are part of the annual routine: flow meters, pressure gauges, transducers and other test devices. The annex asks for equipment calibrated within the last 12 months by an approved facility, gauges with an accuracy of 1% of full scale or better, Bourdon tube gauges used up to 75% of scale and snubbers on all of them. With a flow meter piped back to suction, the annual calibration applies to the meter’s sensing devices.

On a diesel pump, the fuel is tested annually, and the tank is checked every year for water and foreign materials. To have the right reference from the first test, ask for the curve with the set.

5. Weekly inspection and maintenance of the pump room

The weekly pump room inspection checks a temperature of at least 4 °C (40 °F), or 21 °C (70 °F) in a diesel pump room without engine heaters, ventilating louvers free to operate, no excessive water on the floor and the coupling guard in place. On the pump, the suction, discharge and bypass valves are fully open, the piping does not leak and suction line and system pressures are normal.

The NFPA 25 annex notes that experience has shown closed valves to be the primary cause of failure of water-based fire protection systems in protected occupancies.

Also checked are the suction reservoir water level, wet pit suction screens in place and unobstructed, and the waterflow test valves closed, with no water in the test line. In the electrical system, the controller and transfer switch power pilot lights are on, the isolating switch is closed and the reverse phase alarm light is off; the oil level in the vertical motor sight glass and power to the jockey pump are also checked.

In the diesel system, the weekly inspection checks a fuel tank at least two-thirds full, the controller selector switch in auto, normal battery voltage and charging current, battery failure and alarm pilot lights off, the engine running time meter reading, crankcase and right-angle gear drive oil at level, cooling water visible at level, electrolyte above the battery plates, terminals free of corrosion and the water-jacket heater operating.

For hydrants and hose reels, NBR 13714 adds its own routine. The periodic inspection is done by the fire brigade or by specially trained personnel and asks, among other items, whether the pump automation manifold is fit for use and whether the automation is as specified.

For maintenance, NFPA 25 calls for changing the diesel engine lubricating oil, oil filter and fuel filter every 50 operating hours or once a year; pump and motor bearings and coupling annually or as required; batteries, electrical connections and pressure gauges and sensors annually; and power transmission components with elastomeric materials every five years or per the manufacturer. The controller, electric motor and diesel engine follow the manufacturer.

The NBR 13714 maintenance plan includes checking pressure control devices and instruments and meters, inspecting and cleaning electrical connections, checking, adjusting or replacing motor and pump packings, with the lubrication indicated by the manufacturer, and inspecting control and alarm panels. Without manufacturer recommendations for preventive maintenance, the NFPA 25 annex provides an alternative table.

Frequent jockey pump starts call for investigating losses, settings and controls, without assuming leakage is the only cause. The NFPA 25 annex gives a clue before starting: gauge readings higher than suction pressure indicate leakage back from system pressure through the fire pump or the jockey pump.

On a horizontal pump with packing, the same annex asks for checking that the drip pockets under the packing glands drain properly: standing water there is the most common cause of bearing failure. The packing needs about one drop per second to stay lubricated.

Electrical safety is part of the routine too. Because the electric fire pump supply often has no upstream overcurrent protection, opening an energized controller exposes the technician to shock and arc flash. NFPA 25 now requires the safe work practices of NFPA 70E, or an equivalent, in addition to legally required precautions, and relieves readings and inspections that could only be done by opening an energized controller.

6. Documentation, fire certificate and legal responsibility in Brazil

In Brazil, responsibility for maintenance appears in the rules themselves. The São Paulo IT 22 commissioning and inspection report model ends with the responsible engineer attesting conformity and recording that the owner or the person responsible for use is aware of the maintenance and periodic inspection responsibilities under NBR 13714. In the Federal District, NT 13 places the maintenance of automatic sprinklers on the owner or the user.

The same NT 13 requires that work to be done by professionals or companies accredited by the Federal District Fire Department, under technical responsibility. In São Paulo, when renewing the inspection of a sprinklered building, IT 23 recommends that the engineer responsible for maintenance fill in the inspection report of its Annex C, obtain the signature of the owner or the person responsible for use and keep the document on file in the building.

For the pump, that model asks for the performance curve prepared by the manufacturer before installation, a curve produced in the last 36 months, shut-off valves locked fully open, the flow meter and the test header for the annual test, and the alarm panel with the pump supervision events. These items show what the maintenance records need to support at renewal.

Assign responsibility for inspection, testing, maintenance, fault communication and restoration. Management needs to know who acts, who receives the records and how an impairment will be handled. A written contract does not replace doing the work, and the consequences for permits and insurance depend on the rules and terms that apply to each building.

When specifying an FB Bombas set, confirm the manuals, acceptance records and included services in the proposal. FB Bombas offers three post-sale services: replacement of an installed pump with a complete FB pump, start-up and commissioning, and maintenance contracts for FB equipment. Service format, coverage and parts depend on the contracted supply and are defined in the proposal.